// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "storage/browser/fileapi/local_file_stream_reader.h"

#include <stddef.h>
#include <stdint.h>

#include <memory>
#include <string>

#include "base/files/file.h"
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/files/scoped_temp_dir.h"
#include "base/location.h"
#include "base/macros.h"
#include "base/run_loop.h"
#include "base/single_thread_task_runner.h"
#include "base/threading/thread.h"
#include "net/base/io_buffer.h"
#include "net/base/net_errors.h"
#include "net/base/test_completion_callback.h"
#include "testing/gtest/include/gtest/gtest.h"

using storage::LocalFileStreamReader;

namespace content {

namespace {

    const char kTestData[] = "0123456789";
    const int kTestDataSize = arraysize(kTestData) - 1;

    void ReadFromReader(LocalFileStreamReader* reader,
        std::string* data, size_t size,
        int* result)
    {
        ASSERT_TRUE(reader != NULL);
        ASSERT_TRUE(result != NULL);
        *result = net::OK;
        net::TestCompletionCallback callback;
        size_t total_bytes_read = 0;
        while (total_bytes_read < size) {
            scoped_refptr<net::IOBufferWithSize> buf(
                new net::IOBufferWithSize(size - total_bytes_read));
            int rv = reader->Read(buf.get(), buf->size(), callback.callback());
            if (rv == net::ERR_IO_PENDING)
                rv = callback.WaitForResult();
            if (rv < 0)
                *result = rv;
            if (rv <= 0)
                break;
            total_bytes_read += rv;
            data->append(buf->data(), rv);
        }
    }

    void NeverCalled(int) { ADD_FAILURE(); }
    void EmptyCallback() { }

    void QuitLoop()
    {
        base::MessageLoop::current()->QuitWhenIdle();
    }

} // namespace

class LocalFileStreamReaderTest : public testing::Test {
public:
    LocalFileStreamReaderTest()
        : file_thread_("FileUtilProxyTestFileThread")
    {
    }

    void SetUp() override
    {
        ASSERT_TRUE(file_thread_.Start());
        ASSERT_TRUE(dir_.CreateUniqueTempDir());

        base::WriteFile(test_path(), kTestData, kTestDataSize);
        base::File::Info info;
        ASSERT_TRUE(base::GetFileInfo(test_path(), &info));
        test_file_modification_time_ = info.last_modified;
    }

    void TearDown() override
    {
        // Give another chance for deleted streams to perform Close.
        base::RunLoop().RunUntilIdle();
        file_thread_.Stop();
        base::RunLoop().RunUntilIdle();
    }

protected:
    LocalFileStreamReader* CreateFileReader(
        const base::FilePath& path,
        int64_t initial_offset,
        const base::Time& expected_modification_time)
    {
        return new LocalFileStreamReader(
            file_task_runner(),
            path,
            initial_offset,
            expected_modification_time);
    }

    void TouchTestFile(base::TimeDelta delta)
    {
        base::Time new_modified_time = test_file_modification_time() + delta;
        ASSERT_TRUE(base::TouchFile(test_path(),
            test_file_modification_time(),
            new_modified_time));
    }

    base::SingleThreadTaskRunner* file_task_runner() const
    {
        return file_thread_.task_runner().get();
    }

    base::FilePath test_dir() const { return dir_.GetPath(); }
    base::FilePath test_path() const
    {
        return dir_.GetPath().AppendASCII("test");
    }
    base::Time test_file_modification_time() const
    {
        return test_file_modification_time_;
    }

    void EnsureFileTaskFinished()
    {
        file_task_runner()->PostTaskAndReply(
            FROM_HERE, base::Bind(&EmptyCallback), base::Bind(&QuitLoop));
        base::RunLoop().Run();
    }

private:
    base::MessageLoopForIO message_loop_;
    base::Thread file_thread_;
    base::ScopedTempDir dir_;
    base::Time test_file_modification_time_;
};

TEST_F(LocalFileStreamReaderTest, NonExistent)
{
    base::FilePath nonexistent_path = test_dir().AppendASCII("nonexistent");
    std::unique_ptr<LocalFileStreamReader> reader(
        CreateFileReader(nonexistent_path, 0, base::Time()));
    int result = 0;
    std::string data;
    ReadFromReader(reader.get(), &data, 10, &result);
    ASSERT_EQ(net::ERR_FILE_NOT_FOUND, result);
    ASSERT_EQ(0U, data.size());
}

TEST_F(LocalFileStreamReaderTest, Empty)
{
    base::FilePath empty_path = test_dir().AppendASCII("empty");
    base::File file(empty_path, base::File::FLAG_CREATE | base::File::FLAG_READ);
    ASSERT_TRUE(file.IsValid());
    file.Close();

    std::unique_ptr<LocalFileStreamReader> reader(
        CreateFileReader(empty_path, 0, base::Time()));
    int result = 0;
    std::string data;
    ReadFromReader(reader.get(), &data, 10, &result);
    ASSERT_EQ(net::OK, result);
    ASSERT_EQ(0U, data.size());

    net::TestInt64CompletionCallback callback;
    int64_t length_result = reader->GetLength(callback.callback());
    if (length_result == net::ERR_IO_PENDING)
        length_result = callback.WaitForResult();
    ASSERT_EQ(0, result);
}

TEST_F(LocalFileStreamReaderTest, GetLengthNormal)
{
    std::unique_ptr<LocalFileStreamReader> reader(
        CreateFileReader(test_path(), 0, test_file_modification_time()));
    net::TestInt64CompletionCallback callback;
    int64_t result = reader->GetLength(callback.callback());
    if (result == net::ERR_IO_PENDING)
        result = callback.WaitForResult();
    ASSERT_EQ(kTestDataSize, result);
}

TEST_F(LocalFileStreamReaderTest, GetLengthAfterModified)
{
    // Touch file so that the file's modification time becomes different
    // from what we expect.
    TouchTestFile(base::TimeDelta::FromSeconds(-1));

    std::unique_ptr<LocalFileStreamReader> reader(
        CreateFileReader(test_path(), 0, test_file_modification_time()));
    net::TestInt64CompletionCallback callback;
    int64_t result = reader->GetLength(callback.callback());
    if (result == net::ERR_IO_PENDING)
        result = callback.WaitForResult();
    ASSERT_EQ(net::ERR_UPLOAD_FILE_CHANGED, result);

    // With NULL expected modification time this should work.
    reader.reset(CreateFileReader(test_path(), 0, base::Time()));
    result = reader->GetLength(callback.callback());
    if (result == net::ERR_IO_PENDING)
        result = callback.WaitForResult();
    ASSERT_EQ(kTestDataSize, result);
}

TEST_F(LocalFileStreamReaderTest, GetLengthWithOffset)
{
    std::unique_ptr<LocalFileStreamReader> reader(
        CreateFileReader(test_path(), 3, base::Time()));
    net::TestInt64CompletionCallback callback;
    int64_t result = reader->GetLength(callback.callback());
    if (result == net::ERR_IO_PENDING)
        result = callback.WaitForResult();
    // Initial offset does not affect the result of GetLength.
    ASSERT_EQ(kTestDataSize, result);
}

TEST_F(LocalFileStreamReaderTest, ReadNormal)
{
    std::unique_ptr<LocalFileStreamReader> reader(
        CreateFileReader(test_path(), 0, test_file_modification_time()));
    int result = 0;
    std::string data;
    ReadFromReader(reader.get(), &data, kTestDataSize, &result);
    ASSERT_EQ(net::OK, result);
    ASSERT_EQ(kTestData, data);
}

TEST_F(LocalFileStreamReaderTest, ReadAfterModified)
{
    // Touch file so that the file's modification time becomes different
    // from what we expect. Note that the resolution on some filesystems
    // is 1s so we can't test with deltas less than that.
    TouchTestFile(base::TimeDelta::FromSeconds(-1));
    std::unique_ptr<LocalFileStreamReader> reader(
        CreateFileReader(test_path(), 0, test_file_modification_time()));
    int result = 0;
    std::string data;
    ReadFromReader(reader.get(), &data, kTestDataSize, &result);
    EXPECT_EQ(net::ERR_UPLOAD_FILE_CHANGED, result);
    EXPECT_EQ(0U, data.size());

    // Due to precision loss converting int64_t->double->int64_t (e.g. through
    // Blink) the expected/actual time may vary by microseconds. With
    // modification time delta < 10us this should work.
    TouchTestFile(base::TimeDelta::FromMicroseconds(1));
    data.clear();
    reader.reset(CreateFileReader(test_path(), 0, test_file_modification_time()));
    ReadFromReader(reader.get(), &data, kTestDataSize, &result);
    EXPECT_EQ(net::OK, result);
    EXPECT_EQ(kTestData, data);

    // With matching modification times time this should work.
    TouchTestFile(base::TimeDelta());
    data.clear();
    reader.reset(CreateFileReader(test_path(), 0, test_file_modification_time()));
    ReadFromReader(reader.get(), &data, kTestDataSize, &result);
    EXPECT_EQ(net::OK, result);
    EXPECT_EQ(kTestData, data);

    // And with NULL expected modification time this should work.
    data.clear();
    reader.reset(CreateFileReader(test_path(), 0, base::Time()));
    ReadFromReader(reader.get(), &data, kTestDataSize, &result);
    EXPECT_EQ(net::OK, result);
    EXPECT_EQ(kTestData, data);
}

TEST_F(LocalFileStreamReaderTest, ReadWithOffset)
{
    std::unique_ptr<LocalFileStreamReader> reader(
        CreateFileReader(test_path(), 3, base::Time()));
    int result = 0;
    std::string data;
    ReadFromReader(reader.get(), &data, kTestDataSize, &result);
    ASSERT_EQ(net::OK, result);
    ASSERT_EQ(&kTestData[3], data);
}

TEST_F(LocalFileStreamReaderTest, DeleteWithUnfinishedRead)
{
    std::unique_ptr<LocalFileStreamReader> reader(
        CreateFileReader(test_path(), 0, base::Time()));

    net::TestCompletionCallback callback;
    scoped_refptr<net::IOBufferWithSize> buf(
        new net::IOBufferWithSize(kTestDataSize));
    int rv = reader->Read(buf.get(), buf->size(), base::Bind(&NeverCalled));
    ASSERT_TRUE(rv == net::ERR_IO_PENDING || rv >= 0);

    // Delete immediately.
    // Should not crash; nor should NeverCalled be callback.
    reader.reset();
    EnsureFileTaskFinished();
}

} // namespace content
